It has been known for a long time to use a rack and pinion system for raising scaffolding work platforms or elevator cages. Due to the frictional contact of the pinion teeth with the rack teeth, it is necessary to grease the teeth from time to time. Such a greasing operation is time-consuming and difficult to perform on the rack of an outside scaffolding assembly. Such rack is normally secured to a tower which may rise several stories. Falling particles may often adhere to the greased teeth and cause malfunctioning of the raising system because of poor meshing engagement of the pinion with the rack.